For current automobiles, there is a request for reduction of harmful exhaust gas substances, such as carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxides (NOx), contained in an exhaust gas of the automobile from a viewpoint of environment protection. In order for such reduction, an in-cylinder injection type internal combustion engine, which directly injects fuel into a combustion chamber of the internal combustion engine, has been developed.
The in-cylinder injection type internal combustion engine is configured to perform the injection of fuel using a fuel injection valve directly inside the combustion chamber of a cylinder, promotes burning of the injected fuel by decreasing a particle size of the fuel to be injected from the fuel injection valve, and achieves the reduction of harmful exhaust gas substances, improvement of output of the internal combustion engine, and the like.
Further, high current is caused to flow at the time of opening the fuel injection valve since the high-pressure fuel is injected from the fuel injection valve inside the cylinder in the in-cylinder injection type internal combustion engine. Thus, a fuel control device for an in-cylinder injection type internal combustion engine includes a boost circuit and is configured to cause high current to flow to a fuel injection valve using a generated boost voltage as disclosed in JP 2013-39398 A (PTL 1), for example. In addition, control is executed such that the boost voltage is observed by a boost voltage detection unit, a boosting operation is stopped when the boost voltage reaches a prescribed value, and the boosting operation is started again when the boost voltage decreases by a voltage of a predetermined value or more from the prescribed value in order to generate the appropriate boost voltage using the boost circuit.